1. Field of the Invention
The present invention relates to a liquid-cooling system for electronic circuit components, such as semiconductor chips or integrated circuit chips (IC), mounted on a printed circuit board. More particularly, the present invention relates to a printed circuit board assembly including a printed circuit board having electronic circuit components mounted on both front and back faces and cooled by liquid-cooling modules arranged on both sides of the printed circuit board.
2. Description of the Related Art
A typical liquid-cooling plate assembly used for cooling circuit components mounted on a printed circuit board or boards, is disclosed in U.S. Pat. No. 4,155,402. In this liquid-cooling plate assembly, a liquid-cooled, cold plate with a compliant mat interface made of a heat conductive, electrically insulating compliant structure is arranged in compressive contact with diverse circuit components on a printed circuit board so that intimate contact can be achieved with the circuit components, in spite of differences in the relative heights and shapes of the circuit components. The conventional liquid-cooling plate assembly, however, is intended to be fastened to the printed circuit board in such a manner that only the circuit components mounted on one face of the board are cooled when the liquid cooled, cold plate is brought into compressive contact with the components via the compliant mat interface. That is, the printed circuit board is subjected to a one-way pressure acting on one face of the board, and as a result, it is difficult to avoid sagging or deflection in the printed circuit. board. Consequently, the circuit components on the printed circuit board must suffer from mechanical stress. Further, since the larger the size of the printed circuit board, the larger the amount of sag in the printed circuit board, it is not always possible to ensure that all of the circuit components on the face of the board are uniformly cooled. Moreover, in the conventional liquid-cooling plate assembly, the cold plate is cooled by liquid coolant flowing through channels formed in the cold plate, and a rather thick layer of solid plate remains between the liquid coolant flowing through the channels and the face of the liquid-cooling plate assembly in contact with the circuit components.